The long-term objective of this research is to develop a functional model of the neuroanatomy underlying the perception of speech prosody. The working hypothesis is that both hemispheres have attention-driven, task-dependent schemata for speech processing, and that those of the left hemisphere are responsible for linguistic information irrespective of acoustic cues, whereas those of the right hemisphere are prosody specific. To test this hypothesis, PET imaging techniques are employed to observe cerebral blood flow of the human brain in vivo while normal adult, Chinese-English bilinguals and English monolinguals perform perceptual judgments of natural and filtered Chinese and English speech stimuli. Specific aims are to identify neuroanatomical regions involved with the perceptual processing of various aspects of speech prosody at the word- and sentence-level in Chinese and English. Experiment 1 focuses on perceptual processing of word-level Chinese tones. Experiments 2-4 focus on perceptual processing of functionally equivalent, sentence-level aspects of linguistic and affective prosody in both Chinese and English. Chinese, a tone language, allows for the exploration of aspects of speech prosody ranging from the word level to the sentence level of English, a non-tone language, and to distinguish neural circuitry shared in common across languages from those directly attributable to language experience. Bilingual (Chinese-English) and monolingual (English) subjects and two sets of functionally-equivalent language stimuli (Chinese; English) allow for a comparison of neural circuitry underlying perceptual processing of speech prosody in bilingual and monolingual brains.